问题
单项选择题
建立一个视图salary，该视图包括了系号和(该系的)平均工资两个字段，正确的SQL语句是( )。
A．CREATE VIEW salary AS 系号，AVG(工资) AS 平均工资 FROM 教师 GROUP BY 系号
B．CREATE VIEW salary AS SELECT 系号，AVG(工资) AS 平均工资 FROM 教师 GROUP BY 系名
C．CREATE VIEW salary SELECT 系号，AVG(工资) AS 平均工资 FROM 教师；GROUP BY 系号
D．CREATE VIEW salary AS SELECT 系号，AVG(工资) AS 平均工资 FROM 教师；GROUP BY 系号
答案
参考答案：D
解析： 定义视图的SQL语法为CREATE VIEW view_name AS select…statenment，选项B中，用于指定分组条件设置错误，教师表中没有“系名”字段，而A和C选项语法错误。